Modern integrated circuits (ICs) are made up of literally millions of active devices, such as diodes and transistors, and passive devices, such as inductors, capacitors and resistors. To increase manufacturing throughput and lower manufacturing costs, the ICs are manufactured in semiconductor wafers, each containing many identical semiconductor chips. After the ICs are manufactured, semiconductor chips are sawed from the wafers and packaged before they can be used.
In some packaging processes, semiconductor chips (also referred to as dies) are first attached to package substrates. This includes physically securing the semiconductor chips on the package substrates and connecting bonding pads on the semiconductor chips to bonding pads on the package substrates. Underfill, which comprises epoxy, is used to further secure the bonding. The semiconductor chips may be bonded using either flip-chip bonding or wire bonding. Flip-chip bonding utilizes metal bumps to establish electrical contact between a chip's contact pads and the package substrate.
However, there are challenges to implementing such features and processes in IC fabrication. For example, delamination may occur between inter-metal dielectric (IMD) layers overlying the ICs due to high stress from a metal bump, thereby increasing the likelihood of an open circuit.